Am I as a parent of a child attending a private high school in Phila, PA have any rights to another students paper without having their

Am I as a parent of a child attending a private high school in Phila, PA have any rights to another students paper without having their name on it. My daughter was accused of plagiarizing a summer assignment. I have another students paper that shows that she also plagiarized on her assignment . I did not mention any names to the principal because I did not want to get her in trouble also. She gave me her paper and she even admitted to me that she did the same thing as my daughter. The principal wanted the name and the paper. I refused. My daughter got an F the other girl got a B. They did use different articles for their papers but they both still plagiarized. The principal said that under HIPAA laws I had no right to see any other students papers. Is this true even if they black out the names? Please help. Thank Yoou